Joint Precoded and Unprecoded SRS Transmission for Uplink Scheduling
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Solution Overview
Problem
Current wireless communication systems lack the flexibility and efficiency in uplink performance due to the exclusive use of either precoded or unprecoded sounding reference signals, which limits the information available for downlink and uplink scheduling, and coordinated multipoint processing.
Innovation Solution
Transmitting both precoded and unprecoded sounding reference signals from user equipment to base stations, allowing for flexible use of these signals in scheduling resources, such as resource block allocation and rank assignment, and enabling the eNodeB to determine the appropriate precoding for data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only unprecoded sounding reference signals are transmitted, then the system maintains simplicity in signal transmission, but uplink performance and scheduling flexibility are reduced due to lack of beam steering information
Solution Approach 1:
The patent combines both precoded and unprecoded sounding reference signals in the same uplink transmission. The UE transmits unprecoded SRS on certain antenna ports while applying precoding matrices to other antenna ports, allowing the eNB to receive both types of signals simultaneously for comprehensive channel state information and flexible scheduling decisions.
Solution Approach 2:
The system dynamically selects which antenna ports transmit precoded SRS and which transmit unprecoded SRS based on channel conditions and scheduling requirements. The precoding matrix selection and resource allocation are adapted in real-time to optimize uplink performance while managing complexity.
2Reliability
If only precoded sounding reference signals are transmitted, then beam steering information is available for improved uplink performance, but the eNB lacks unprecoded channel information for accurate downlink scheduling and resource allocation
Solution Approach 1:
The patent merges precoded and unprecoded SRS transmissions so that the eNB receives both beam-steered channel information (from precoded SRS) and raw channel state information (from unprecoded SRS). This comprehensive information set enables accurate downlink scheduling, resource block allocation, and precoding matrix selection without information loss.
3Loss of information
If both precoded and unprecoded sounding reference signals are transmitted simultaneously, then comprehensive channel information is provided for improved scheduling and resource management, but the signaling overhead and processing complexity increase
Solution Approach 1:
The patent segments the antenna ports into different groups: some ports transmit unprecoded SRS while others transmit precoded SRS. This segmentation allows the system to distribute the information-gathering function across different antenna ports, reducing the complexity burden on any single transmission path while maintaining comprehensive channel information.
Solution Approach 2:
The system applies precoding to only a subset of antenna ports rather than all ports, transmitting both precoded and unprecoded SRS. This partial application of precoding reduces the overall processing complexity compared to full precoding, while still providing sufficient channel information for effective scheduling and resource management.
Data Source
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AI summary
Both precoded sounding reference signals (SRS) and unprecoded SRS are transmitted from a UE to an eNB. The UE may transmit both in the same subframe using either TDM or FDM. Or the UE may transmit each in different subframes from each other. The eNB uses some combination of the precoded SRS and the unprecoded SRS in scheduling resources for the UE. The eNB may also provide instruction to the UE for PUSCH precoding for data transmission. The eNB may signal the UE to use the same precoding as for the precoded SRS. The eNB may instead signal the UE to use different precoding by including the precoding information or delta information between the precoding used for the precoded SRS and the selected precoding for the PUSCH data.